Saluting has its roots in prehistory. When two Neanderthals wished to
approach one another it was necessary to demonstrate intent. The hand
which held a weapon, (the right most often) was held above the head,
making one's self vulnerable, so that the other could clearly see that
it was safe to approach. It was many millenia later that it developed
into the more formal military salute of today. On the civilian side,
the friendly wave derived from the same origins.
Charles Stanley
Norfolk, Va.